Modelling ocean acidification in the Nordic and Barents Seas in present and future climate

An ecosystem model, NORWECOM.E2E including a module for the carbonate system, has been used to investigate the effects of rising atmospheric CO2 and climate change on the ocean’s acid–base state in the Nordic and Barents sea. Using the 20C3M control run and the A1B emission scenario, a downscaling of the GISS-AOM global climate model has been used to force the ecosystem model for a reference (1981–2000) and a future climate (2046–2065) simulation respectively. The simulations demonstrates how the saturation state of seawater with respect to aragonite will evolve, with a shoaling of the saturation horizon of approximately 1200 meters in the Nordic Seas, and a large increase in area extent of under saturated surface waters. The simulated pH change in the surface water is − 0.19 from 2000 to 2065, while the model estimates an almost doubling of the CO2 air-sea flux in the Barents Sea increasing the uptake from 23 to 37 gC m− 2 year− 1. The main driver for the modelled changes in surface fCO2 is the change in DIC, with only minor contributions from temperature, salinity and total alkalinity.